Effects of fixed orthodontic treatment with and without chlorhexidine mouthwash on vitality of oral mucosal cells reflected by cell nuclear indexes: A preliminary 3-phase before-after clinical trial.

INTRODUCTION: Effects of mouthwashes on the vitality of oral mucosal cells have not been determined in orthodontic patients. We aimed to assess, for the first time, the effects of fixed orthodontic treatment with and without chlorhexidine (CHX) mouthwash on the oral mucosal cell vitality. MATERIALS AND METHODS: All patients meeting the eligibility criteria were consecutively included until the desired sample size was reached. Oral buccal mucosal cell samples were taken immediately before orthodontic treatment. For each patient, 20 metal brackets and 4 bands were installed on the teeth. Cell samples were recollected after one month of treatment. Then, the patients used an ethanol-free 0.12% CHX mouthwash two times a week for one month. Sampling was repeated at the end of the second month. Papanicolaou staining was used for micronucleus screening of the indexes: micronucleus (MIC), karyorrhexis (KR), karyolysis (KL), and broken eggs (BE). The repair index (RI) was calculated as RI=KR+KL/BE+MIC. Comparisons of nuclear changes over 3 intervals were done using the Friedman and Dunn-Bonferroni tests (α=0.05, ß<0.05). RESULTS: This prospective before-after clinical trial was performed on 408 observations of 34 patients (14 males, 20 females, mean age: 16.68±3.75 years) at 3 intervals (×4 parameters each). The means of MIC, KR, KL, BE, and RI were respectively 1.312±1.219, 0.241±0.564, 0.426±0.657, 0.115±0.224, and 0.476±0.360 before treatment. They were 1.348±1.171, 0.215±0.236, 0.406±0.369, 0.124±0.187, and 0.511±0.310 at the first interval and 1.909±1.263, 0.368±0.174, 0.615±0.269, 0.253±0.150, and 0.529±0.195 at the second interval. Friedman showed significant time-dependent changes for all variables (P<0.0005) except RI. Dunn-Bonferroni showed that except MIC (P=0.017), KR/KL/BE changed insignificantly after orthodontic treatment (P≥0.974). MIC/KR/KL/BE increased significantly after the addition of CHX (P<0.0005). CONCLUSION: CHX mouthwash, together with orthodontic treatment, has a strong deteriorating effect on nuclear indexes associated with the vitality of buccal mucosal cells. Nuclear changes caused by orthodontic treatment alone might be negligible.

Salivary Nickel and Chromium Levels in Orthodontic Patients with and Without Periodontitis: a Preliminary Historical Cohort Study.

Many periodontal patients may need orthodontic treatment. Alterations in oral environment particularly the reduction of pH in periodontal patients could affect metal ion release from orthodontic appliances. However, there is no study on metal ion release in periodontal patients. The aim of this preliminary study was to comparatively evaluate, for the first time, salivary levels of nickel and chromium in periodontal patients (versus healthy controls) under orthodontic treatment for 2 months. In this in vivo study, 40 subjects were evaluated. Patient selection and standardization of orthodontic treatment protocols were prospectively designed and performed. Two groups of n = 20 each (control: healthy orthodontic patients, cohort: orthodontic patients with periodontitis) underwent similar protocols of fixed orthodontic treatment for 2 months. After 2 months, salivary nickel and chromium concentrations of the case and cohort groups were measured using inductively coupled plasma mass spectrometry (ICP-MS). The values were compared between the two groups using t test. There were 10 men and 10 women in each group. The mean age of patients was 34.6 ± 3.6 years old. The salivary level of nickel was 338.2 ± 235.5 ng/ml and 182.8 ± 116.5 ng/ml in the cohort and control groups, respectively (P = 0.0118). The salivary level of chromium was 7.4 ± 3.15 ng/ml in the cohort and 6.35 ± 2.39 ng/ml in the control group (P = 0.2214). Salivary level of nickel might be considerably higher in periodontal patients undergoing 2 months of orthodontic treatment compared to orthodontic patients with healthy gingivae.

Associations among sella turcica bridging, atlas arcuate foramen (ponticulus posticus) development, atlas posterior arch deficiency, and the occurrence of palatally displaced canine impaction.

INTRODUCTION: Head and neck skeletal anomalies or normal variants might predict the occurrence of palatally displaced impacted maxillary canines. Despite their clinical importance, studies in this regard are rare, especially when it comes to vertebral anomalies. METHODS: This case-control study was performed on cephalographs of 35 orthodontic patients (11 male, 24 female) with palatally displaced canines (PDC) and 75 patients without them (29 male, 46 female). PDC were diagnosed on panoramic and lateral cephalographs and from clinical reports. The occurrence and severity of sella turcica bridge and the atlas ponticulus posticus, and deficiency of the posterior atlas arch were evaluated twice on lateral cephalographs. The associations between the occurrence and level of these skeletal anomalies and variations of PDC occurrence as well as additional correlations were assessed using multivariable and bivariate statistics (α = 0.05; ß ≤0.2). RESULTS: The patients' mean age was 18.4 ± 1.9 years. In the control and patient groups, 23 (30.7%) and 21 subjects (60%) had sella turcica bridging, respectively (chi-square, P = 0.003). Ponticulus posticus was observed in 14 (18.7%) controls and 15 (42.9%) patients (chi-square, P = 0.007). Posterior atlas arch deficiency was observed in 4 (5.3%) controls and 5 (14.3%) patients (chi-square, P = 0.111). The presence of ponticulus posticus and sella turcica bridging might be associated with increased odds of PDC occurrence for about odds ratios of 3.1 and 3.5 times, respectively (binary logistic regression). CONCLUSIONS: PDC is positively associated with the occurrence and severity of sella turcica bridging and ponticulus posticus. The association between PDC and posterior atlas arch deficiency was inconclusive.

Associations between occlusion, jaw relationships, craniofacial dimensions and the occurrence of palatally-displaced canines.

BACKGROUND AND PURPOSE: Cephalometric and arch measurements might predict the occurrence of a palatally-displaced impacted maxillary canine (PDC). Despite their clinical importance, studies in this regard are limited and controversial. METHODS: In this case-control study, 35 PDC patients and 77 controls aged over 13 years were examined. Eleven cephalometric measurements: N-S, ANS-PNS, ANS-N, S-N-ANS, facial angle (FH/NPog), SNA, SNB, Y-axis (SN/SGn), gonial angle, Go-Gn/SN, and Jarabak Index were performed. The maxillary and mandibular intermolar and interpremolar widths were measured. Patients' sagittal skeletal relationships and centric occlusions (molar) were measured by radiographic and cast examinations. The differences between the two groups in terms of the above-mentioned cephalometric and anatomic variables were assessed using Chi2 and Mann-Whitney U-tests (α=0.05). RESULTS: Chi2 showed a significant negative association between dentoalveolar class I (molar) and PDC occurrence (P=0.018), but not between PDC and skeletal sagittal relationships. Facial angle (FH/NPog) and Y-axis (SN/SGn) were more obtuse in patients with PDC (P<0.05). No arch dimensions differed between the two groups. CONCLUSIONS: PDC tends to accompany molar class II/III but is not associated with upper or lower jaw widths or lengths. Vertical dimensions might be smaller in PDC patients. Some variables were inconclusive and need future assessments.

Facial Growth Patterns and Insertion Sites of Miniscrew Implants.

INTRODUCTION: We aimed to evaluate the associations between the craniofacial growth pattern with interradicular distances (IRDs), cortical widths (CWs), and jaw heights (JHs). Also, we mapped safe zones for miniscrew implantation. METHODS: Cone-beam computerized tomography data pertaining to 60 Class-I patients were divided into 3 growth groups: normal, horizontal, and vertical. IRDs and CWs were measured for bimaxillary canines to second molars, on buccal and lingual sides, at 3 transverse planes (1, 3, and 5 mm apically to the alveolar crest). JHs were measured in both jaws, between canines and second molars. The role of growth patterns and other variables were analyzed; also, safe zones were mapped with statistical substantiation. RESULTS: IRDs were greater in the mandible, males, at points more distant from the ridge crest, and on the lingual side. Cortexes were thicker in the horizontal growth pattern, mandible, males, older patients, and lingual sides. JHs were greater in vertical growth pattern, mandible, and males. CONCLUSIONS: The cortex might be thicker in patients with a horizontal growth pattern. The height might be greater in vertical growth pattern. IRDs might not be affected by growth pattern.

Effects of fixed orthodontic treatment on nickel and chromium levels in gingival crevicular fluid as a novel systemic biomarker of trace elements: A longitudinal study.

INTRODUCTION: Nickel and chromium might induce hypersensitivity. Therefore, they are of interest to orthodontists. Gingival crevicular fluid (GCF) is highly relevant to orthodontic treatments and might reflect systemic changes associated with the inflammatory response induced by orthodontic forces. Therefore, it might also be used to show metal ion changes. Nevertheless, baseline metal levels of GCF are unknown, and the effect of orthodontic treatment on GCF metal levels has not been investigated. The aim of this study was to assess the levels of nickel and chromium in GCF. METHODS: Based on a pilot study, the sample size was predetermined as 24 × 3 measurements to obtain test powers above 90%. Nickel and chromium concentrations were measured before treatment and 1 month and 6 months later in 12 female and 12 male patients who had fixed orthodontic appliances using atomic absorption spectrophotometry. The gingival index was also evaluated in each session. The effects of treatment on GCF ions were analyzed using repeated-measures analysis of variance and Friedman tests (α = 0.05, ß ≤0.01). RESULTS: The gingival index worsened over time (chi-square test, P <0.001). The mean nickel levels were 3.894 ± 1.442, 5.913 ± 2.735, and 19.810 ± 8.452 µg per gram, respectively, at baseline, month 1, and month 6. Chromium concentrations were 1.978 ± 0.721, 4.135 ± 1.591, and 13.760 ± 3.555 µg per gram, respectively. Compared with the baseline, nickel increased by 150% and 510%, respectively, in the first and sixth months (Friedman, P <0.0001), and chromium increased by 200% and 700%, respectively (analysis of variance, P <0.0001). CONCLUSIONS: Six months of fixed orthodontic treatment might intensify the levels of nickel and chromium in the GCF as well as gingival inflammation.

Soft tissue cephalometric norms of Iranian Class I adults with good occlusions and balanced faces.

AIM: The aim of this study was to assess the soft tissue measurements of Iranians with good occlusion and to compare the Iranian norms with other ethnicities. MATERIALS AND METHODS: A total of 25 anthropometric variables were measured by a dentist in 50 Iranian Class I subjects (25 males, 25 females) with good occlusion and well-balanced faces. The differences between the two genders, as well as the differences between Iranian norms and the Holdaway and Burstone analyses, were statistically analyzed using a t-test (α=0.05). RESULTS: The subjects' mean age was 21.6±4.1 years. There were significant differences between males and females regarding the mentocervical angle, the nasolabial angle, Merrifield's Z-angle, the angle of facial convexity, soft tissue chin thickness, and upper lip thickness (P<0.05). The Holdaway norms can be used for the Iranian population, except for the following measurements which might be significantly different: facial convexity angle, nasolabial angle, interlabial gap, soft tissue facial angle, skeletal profile convexity, H-angle, lower lip to H-line, lower sulcus depth, and soft tissue chin thickness (P<0.05). CONCLUSIONS: There was a considerable sex dimorphism in the Iranian population. The Holdaway norms are not useful for the Iranian population regarding most measurements.

Evaluating the effect of laser irradiation on bone regeneration in midpalatal suture concurrent to rapid palatal expansion in rats.

BACKGROUND: Rapid palatal expansion is one of the most important orthopedic treatments that correct the dental and palatal constriction. Stability of the changes partly depend on the rapidity of new bone formation in affected sutures after expansion. The purpose of this study was to investigate the effect of laser irradiation on the healing of midpalatal suture concurrent to the expansion of midpalatal suture in rats. MATERIALS AND METHODS: A total of 78 male Sprague rats in seven groups were evaluated: A control group of six rats without any treatments and three experimental groups of 24 which underwent palatal expansion for different time periods (7, 14, and 30 days), and each divided into two groups of with and without laser irradiation. Laser therapy was done by gallium-aluminum-arsenide diode laser with 810 nm wavelength and 4 J/cm(2) irradiation in days 0, 2, 4, 6, 8, 10, 12, 14 in 4 points (1 labial and 3 palatal points). After sacrificing, the sections were evaluated by histomorphometric and quantitative analysis and results were statistically investigated by independent samples t-test. RESULTS: The results in 7 days, 14 days, and 30 days show that laser therapy can increase the rate of osteogenesis in palatal suture during rapid palatal expansion but the differences in 7 days groups were not significant (P = 0.117) while in 14 days groups (P = 0.032) and 30 days groups were significant (P = 0.001). Most of effectiveness of low-power laser was seen between 14 and 30 days while the laser therapy was stopped. CONCLUSION: These findings suggest that low-level laser irradiation can increase and accelerate bone regeneration in the midpalatal suture after rapid palatal expansion, hence, reduce retention time.

Effects of fixed orthodontic treatment on hair nickel and chromium levels: a 6-month prospective preliminary study.

Although nickel and chromium are known as allergen and cytotoxic orthodontic metals, very few and controversial studies have assessed the effect of orthodontic treatment on their systemic levels reflected by their best biomarker of exposure, hair. This prospective preliminary study was conducted to evaluate hair nickel and chromium levels in fixed orthodontic patients. Scalp hair nickel/chromium concentrations of 12 female and 12 male fixed orthodontic patients were measured before treatment and 6 months later, using atomic absorption spectrophotometry. The effects of treatment, gender, and age on hair ions were analyzed statistically (α = 0.05). The patients' mean age was 18.38 ± 3.98 years. The mean nickel levels were 0.1380 ± 0.0570 and 0.6715 ± 0.1785 µg/g dry hair mass, respectively, in the baseline and sixth month of treatment. Chromium concentrations were 0.1455 ± 0.0769 and 0.1683 ± 0.0707 µg/g dry hair mass, respectively. After 6 months, nickel increased for 387 % (paired t test P = 0.0000) and chromium increased for 16 % (P = 0.0002). No significant correlations were observed between any ion levels with age or gender (Spearman P > 0.2). Within the limitations of this preliminary study, it seems that 6 months of fixed orthodontic treatment might increase levels of hair nickel and chromium. Future larger studies are necessary to validate these results.

Effects of fixed orthodontic treatment using conventional versus metal-injection molding brackets on salivary nickel and chromium levels: a double-blind randomized clinical trial.

INTRODUCTION: Despite the importance of nickel and chromium release from orthodontic brackets, there are no in vivo or in vitro studies on this issue in the case of metal-injection molding (MIM) brackets. METHODS: Saliva samples were collected from 30 orthodontic patients divided randomly into two groups of conventional and MIM brackets, before treatment and 2 months later. Approved attendees with odd and even numbers were, respectively, assigned to the control and treatment groups. For blinding, the patients were not informed of their bracket types, and the saliva samples were coded. Nickel and chromium levels were determined using atomic absorption spectrophotometry. Data were analysed using repeated-measures two-way analysis of covariance, independent-samples t-test, chi-squared, Spearman and point-biserial correlation coefficients, Mann-Whitney, and Wilcoxon tests (α = 0.05). RESULTS: Mean nickel level increased from 7.87±8.14 (pre-treatment) to 12.57±9.96 (2nd month) in the control group, and from 8.62±9.85 (pre-treatment) to 8.86±6.42 µg/l in the MIM group. Both of these increases were significant (Wilcoxon P < 0.03). Average chromium level changed from 0.25±0.56 (pre-treatment) to 0.35±0.62 and from 0.42±0.48 to 0.26±0.57 µg/l in the MIM group. Only the reduction observed in the MIM group was significant (Wilcoxon P = 0.0438). Age and gender had no significant influence on ion levels (P > 0.1). The differences between both ions' levels measured in the 60th day in both bracket groups were not significant (Mann-Whitney P > 0.05). The extents of changes over time were not significantly different between the bracket types (Mann-Whitney P > 0.05). LIMITATIONS: The sample size was not predetermined based on power calculations. The spectrophotometer was limited to detecting chromium concentrations above 0.25 µg/l. Ion discharge from brackets might continuously change. The current in vivo methods are unable to take such fluctuations into account. CONCLUSION: Nickel might increase in patients undergoing treatment with both bracket types, although the rate of increase might be greater in patients under treatment with conventional brackets. Using MIM brackets might reduce salivary chromium for a trivial but generalizable amount. Still, ion levels leached from conventional versus MIM brackets might not show a difference after 2 months. Age and gender might not affect the ion levels in normal people or orthodontic patients. REGISTRATION: The protocol is registered offline at the university library. PROTOCOL: The protocol was not published before the trail commencement. FUNDING: Self-funded (S. H.). CONFLICT OF INTEREST: None to declare.

Craniofacial morphologic parameters in a Persian population: an anthropometric study.

Limited data are available regarding the reference ranges of facial proportions of the Persian population in Iran. This study aimed to establish the reference range of craniofacial anthropometric measurements in an adult Iranian population. On 100 individuals (men = women), aged 18 to 30 years with normal faces and occlusions, 34 linear and 7 angular measurements as well as 24 indices were calculated. The difference of measurements between men and women were evaluated by paired t-test. The data were compared with the norms of North American whites using 1-sample t-test. The subjects belonged to 5 ethnic groups (57% from Fars, 14% from Kord, 11% from Azari, 10% from Gilaki-Mazani, and 2% from Lor). All head measurements were greater in men except for the head index and the head height. The subjects had leptoprosopic faces. The intercanthal width was almost one third of the biocular width and greater than the eye fissure length. Although the nose width of women was significantly smaller, both sexes had leptorrhine noses. The chin height and lower chin height were greater in men. In comparison with North American whites, considerable differences were found regarding head height and width, biocular width, nose height, face height, mouth width, and upper chin height. In conclusion, the reference range of craniofacial anthropometric measurements established for the Iranian population might be efficiently used for esthetic treatments.

The effect of stress on salivary metal ion content in orthodontic patients.

Psychological stress can alter the environment in favor of corrosion of orthodontic alloys by changing the properties of saliva. This study aimed to assess the effect of stress induction on salivary nickel and chromium content in fixed orthodontic patients. Thirty patients were enrolled in this experiment. Saliva sample collection was performed at four time points: T1, before insertion of orthodontic appliances; T2, 3 months after the initiation of orthodontic treatment, before induction of stress; T3, 15 min following the induction of stress by Trier Social Stress Test; and T4, 30 min following the induction of stress. Ion content was measured by atomic absorption spectrophotometry. The obtained data were analyzed by repeated measures analysis of variance (ANOVA) and post hoc Bonferroni test. The mean amount of salivary nickel increased from 11.9 ± 5.1 µg/L at T1 to 14.1 ± 5.3 µg/L at T4. This increase was found significant only at T4 comparing to T1. The average salivary chromium content changed from 4.1 ± 2.3 µg/L at T1 to 5.1 ± 3.3 µg/L at T4. None of the differences were significant for chromium. In conclusion, induction of stress in this study led to a significant increase in nickel release from orthodontic appliances into saliva. The salivary chromium content however was not significantly altered, yet gradually increased.

A new method to correct lingual rolling of lower molars (Amini twister).

In this report, we present an uncomplicated approach to overcome lingual rolling of mandibular molars during orthodontic treatment, by using rectangular NiTi arch wire in twist fashion through the molar tube. The sequential steps of the twist manoeuvre on a typodont and a case report are exhibited in this article.

A new approach to correct a Class III malocclusion with miniscrews: a case report.

This report presents the treatment of a patient with skeletal Class III relationship in the permanent dentition caused by maxillary hypoplasia. The treatment plan called for palatal expansion and maxillary advancement. Titanium miniscrews were placed in the mandible to facilitate the maxillary protraction after maxillary expansion. An increase of projection of the upper jaw relative to the cranial base and to the lower jaw and significant improvement of the facial profile were observed.

Assessment of the uvulo-glossopharyngeal dimensions in patients with ß-thalassemia major.

OBJECTIVES: Thalassemia patients present varying degrees of craniofacial characteristics, while the morphology of the upper airway is less studied. The purpose of this study was to compare the uvula-glossopharyngeal dimensions (UGDs) of patients with ß-thalassemia major (BTM) with non-thalassemic subjects who had similarities in the maxillo-mandibular skeletal pattern. SUBJECTS AND METHODS: The material for this cross-sectional retrospective study consisted of lateral cephalograms of 40 BTM patients (23 males, 17 females, aged 9.5 ± 0.97 years). These were compared with lateral cephalograms of a control group of 40 non-thalassemic subjects (23 males, 17 females, aged 11.0 ± 0.87 years). The control group was chosen so that they had similarities with the BTM patients in the following cephalometric variables: SNA (in degree), SNB (in degree), ANB (in degree), and anterior facial height (N-Me). RESULTS: The following UGDs in thalassemic subjects were significantly shorter in patients with BTM: tongue length (P < 0.05), the distance between the hyoid bone and the mandibular plane (P < 0.01), and the vertical distance between hyoid bone and the C3-RGN line (line connecting third vertebra and retrognathion) (P < 0.05). The middle airway space in BTM patients was significantly wider (P < 0.05), and a trend was observed for the wider inferior airway space (P = 0.07). CONCLUSIONS: Based on this study, some UGDs in BTM patients were significantly different, compared to non-thalassemic subjects who had a similar maxillo-mandibular skeletal pattern. These findings may have implications for the long-term treatment of BTM patients; however, since groups were not exactly age-matched, the observed differences between groups could be attributed to either BTM, age, or both. Additional studies with age-matched subjects are needed to investigate the relationship between BTM and UGDs.

Soft-tissue profile characteristics in children with beta thalassaemia major.

OBJECTIVES: To compare soft-tissue profile characteristics of patients with beta thalassaemia major (BTM) with a group of non-thalasseamic subjects with a similar skeletal pattern. SUBJECTS AND METHODS: The material for this cross-sectional retrospective study consisted of lateral cephalograms of 40 BTM patients (23 males, 17 females, aged 9.5 ± 0.97 years). These were compared with lateral cephalograms of a control group of 40 non-thalasseamic subjects (23 males, 17 females, aged 11.0 ± 0.87 years) who had similarities with the study group in the following cephalometric variables: SNA (°), SNB (°), ANB (°) and anterior face height (N-Me). Overall, 22 linear and angular soft-tissue cephalometric variables were measured. RESULTS: Horizontal soft-tissue measurements, except for the thickness at B point (B-B'), were larger relative to non-thalasseamic subjects; particularly showing a statistically larger mean values for the following variables: soft-tissue thickness at Pronasale (ANS-Prn, p < 0.01), Subnasale (ANS-Sn, p < 0.01), point A (A-A', p < 0.01) and at the Pogonion point (Pg-Pg', p < 0.05). Compared to controls, BTM patients showed significantly larger (p < 0.05) mean values for the anterior nose length (Prn-Prn', p < 0.01) and lower nose height (Prn-Sn, p < 0.05). Variables that represented the lip profile, including the nasolabial angle, did not significantly differ from controls. The average values for the mid-face (N-ANS), posterior face height (S-Go) and the inclination of maxillary incisors to the SN plane were significantly larger (p < 0.01) in BTM patients. CONCLUSION: The soft-tissue profile differences in BTM patients may have implications for their future orthodontic or orthognathic management. Future studies can investigate the 3D soft-tissue changes and the possible contributing factors.

Prevalence and Pattern of Accessory Teeth (Hyperdontia) in Permanent Dentition of Iranian Orthodontic Patients.

BACKGROUND: Awareness of hyperdontia pattern/prevalence can be useful in early diagnosis and prevention by general practitioners, pediatric dentists, and orthodontists. Since the previous results regarding the pattern of hyperdontia (supernumerary teeth) are controversial, this study aimed to assess this subject among Iranian orthodontic patients. METHODS: All approved panoramic radiographs of 3374 orthodontic patients (aged 10 to 20 years old) who had visited orthodontic departments of all Tehran dentistry universities and 10 private clinics during the years 1999-2009 were investigated to establish the prevalence/pattern of hyperdontia in permanent dentition (excluding third molars). The data were analyzed using a chi-square, a chi-square goodness-of-fit, and a Fisher exact test (α=0.05). RESULTS: Of the patients, 2012 were female and 1362 were male. The prevalence of hyperdontia was 0.72% (14 females [0.69% of females], 10 males [0.73% of males], female-to-male ratio=1:1.055). The difference between the genders was not significant (P = 0.896). No double or multiple supernumeraries were found. The most common accessory teeth were mesiodens (58.3%), maxillary laterals (25%), and maxillary premolars (16.7%). Hyperdontia was significantly more common (P=0.000) in maxilla (there was only one mandibular accessory tooth). It was more frequent in the anterior segment (P=0.000). However the occurrence was not significantly different between bimaxillary right and left quadrants (P=0.6). CONCLUSION: Hyperdontia was more common in premaxilla, and the most common accessory tooth was mesiodens. Unlike earlier studies, no bilateral accessory teeth were found. Also no gender dimorphism was discerned.

Variations in surface roughness of seven orthodontic archwires: an SEM-profilometry study.

OBJECTIVE: The purpose of this study was to evaluate the surface roughness (SR) of 2 types of orthodontic archwires made by 4 different manufacturers. METHODS: This in vitro experimental study was conducted on 35 specimens of 7 different orthodontic archwires, namely, 1 nickel-titanium (NiTi) archwire each from the manufacturers American Orthodontics, OrthoTechnology, All-Star Orthodontics, and Smart Technology, and 1 stainless steel (SS) archwire each from the manufacturers American Orthodontics, OrthoTechnology, and All-Star Orthodontics. After analyzing the composition of each wire by energy-dispersive X-ray analysis, the SR of each wire was determined by scanning electron microscopy (SEM) and surface profilometry. Data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests (α < 0.05). RESULTS: The average SR of NiTi wires manufactured by Smart Technology, American Orthodontics, OrthoTechnology, and All-Star Orthodontics were 1,289 ± 915 A°, 1,378 ± 372 A°, 2,444 ± 369 A°, and 5,242 ± 2,832 A°, respectively. The average SR of SS wires manufactured by All-Star Orthodontics, OrthoTechnology, and American Orthodontics were 710 ± 210 A°, 1,831 ± 1,156 A°, and 4,018 ± 2,214 A°, respectively. Similar to the results of profilometry, the SEM images showed more defects and cracks on the SS wire made by American Orthodontics and the NiTi wire made by All-Star Orthodontics than others. CONCLUSIONS: The NiTi wire manufactured by All-Star Orthodontics and the SS wire made by American Orthodontics were the roughest wires.

Prevalence and pattern of hypodontia in the permanent dentition of 3374 Iranian orthodontic patients.

BACKGROUND: Hypodontia is the most common dental anomaly and might cause clinical complications. The aim of this study was to assess the prevalence and pattern of congenital missing in the permanent dentition dentition (excluding third molars), among Iranian orthodontic patients. MATERIALS AND METHODS: In this descriptive cross-sectional study, all approved panoramic radiographs of 3374 orthodontic patients (aged 10 to 20 years old), who had visited the Orthodontic Departments of all Tehran Dentistry Universities and 10 private clinics during the years 1999 to 2009 were investigated, to establish the prevalence of hypodontia in the permanent dentition (excluding third molars). The data were analyzed using a chi-square test (α = 0.01). RESULTS: Included were 2012 female and 1362 male patients. The prevalence of hypodontia was 5.21% (5.86% in females, 4.25% in males). The difference between the genders in terms of missing teeth was not significant (P = 0.202). A total of 298 teeth were missing (166 in females, 132 in males). The average of missing per individual was found to be 1.69 (1.40 missing for each girl, 2.32 for each boy). There was no significant difference between the number of missing teeth in males and females (P = 0.160). The most common missing teeth were maxillary lateral incisors (37.2%), mandibular second premolars (22.1%), and mandibular central incisors (10.7%). In both unilateral and bilateral hypodontia cases, the maxillary lateral had the highest prevalence of missing, followed by the mandibular second premolar. Missing was significantly more frequent (P = 0.001) in the maxilla (5.3%) compared to the mandible (3.5%). CONCLUSION: Out of every 20 Iranian orthodontic patients, one might have some missing permanent teeth, needing early attention. Hypodontia was more prevalent in females (though not significantly) and in the maxilla. Although more females were affected, the number of missing per individual was greater in males.